Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Car Audio and Multimedia

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 01-28-2008, 09:04 AM
bustedbenz's Avatar
Registered User
 
Join Date: Feb 2007
Location: Valle Crucis, NC
Posts: 2,283
I can hear my alternator in my radio

... it's a rebuilt alternator, from McParts (But it's a really nice local guy McParts, not a chain store McParts) - within the last year and a half.

Does that mean it's going bad or just that 21 year old wiring insulation isn't doing its job?

No reason to suspect failure, it's charging perfectly according to a multimeter. Just didn't know if that was symptom # 1 of bad alternators or symptom # 1 of old cars with old wiring.

__________________


~Michael S.~
Past cars:

1986 300SDL
1987 300SDL
1982 240D
1982 300SD


Current:

1987 300SDL
Reply With Quote
  #2  
Old 01-28-2008, 09:06 AM
ForcedInduction
Guest
 
Posts: n/a
Check that the cable going into the power antenna is securely plugged in.
Reply With Quote
  #3  
Old 01-28-2008, 10:54 AM
Biodiesel300TD's Avatar
|3iodiesel300T|)
 
Join Date: Dec 2004
Location: Albany, OR
Posts: 4,845
Do your headlights brighten if you step on the pedal at all? If so they I would try a new voltage regulator. It's on the back of the alternator, and there are two screws holding it in place.
__________________
Andrew
'04 Jetta TDI Wagon
'82 300TD ~ Winnie ~ Sold
'77 300D ~ Sold
Reply With Quote
  #4  
Old 01-28-2008, 11:05 AM
mobetta's Avatar
(Oo{-I-}oO)
 
Join Date: Mar 2006
Location: minnesota,hey.
Posts: 1,841
Stock radio?
__________________
1984 123.193 372,xxx miles, room for Seven.

1999 Dodge Durango Cummins 4BTAA 47RE 5k lb 4x4 getting 25+mpgs, room for Seven.
Reply With Quote
  #5  
Old 01-28-2008, 05:48 PM
toomany MBZ's Avatar
Registered User
 
Join Date: Nov 2006
Location: central Va
Posts: 7,820
Inside the front wheel bearing caps were springs of some sort to negate this, many are no longer on the wheels.
__________________
83 SD

84 CD
Reply With Quote
  #6  
Old 01-28-2008, 05:50 PM
TX76513's Avatar
Platinum Member
 
Join Date: Apr 2003
Location: Brandon, Mississippi
Posts: 5,209
Quote:
Originally Posted by toomany MBZ View Post
Inside the front wheel bearing caps were springs of some sort to negate this, many are no longer on the wheels.
I am voting with toomany MBZ Radio supression contact. I don't know how (why) that gizmo works but if you don't put them back in after you do your wheel bearing you will hear your alternator through your radio.
__________________
BENZ THERE DONE THAThttp://www.peachparts.com/shopforum/...c/progress.gif
15 VW Passat TDI
00 E420
98 E300 DT
97 E420 Donor Car - NEED PARTS? PM ME!
97 S500
97 E300D
86 Holden Jackaroo Turbo D
86 300SDL
(o\|/o)
Reply With Quote
  #7  
Old 01-28-2008, 07:43 PM
Registered User
 
Join Date: Sep 2001
Location: central Texas
Posts: 17,281
If you can hear it when the car is not moving ( its wheels) then it is probably something else... check to see if you have any electrolytic capacitors either on the radio or on the alternator or wiring.... they leak and dry up over time.... and are often used in filtering circuits for this kind of deal.... on old plug in audio stuff...when this capacitor goes out you hear the 60 hrtz of the line voltage...
Reply With Quote
  #8  
Old 01-28-2008, 08:06 PM
BoomInTheTrunk's Avatar
Registered User
 
Join Date: Sep 2007
Location: Rancho Cucamunga, California
Posts: 713
possibly a bad ground check all the grounds on the radio.
Reply With Quote
  #9  
Old 01-28-2008, 10:01 PM
Palangi's Avatar
L' Résistance
 
Join Date: Dec 2000
Location: Republique de Banana
Posts: 3,496
Alternator whine in the radio can be caused by a failed diode in the alternator.
__________________
Palangi

2004 C240 Wagon 203.261 Baby Benz
2008 ML320 CDI Highway Cruiser
2006 Toyota Prius, Saving the Planet @ 48 mpg
2000 F-150, Destroying the Planet @ 20 mpg



TRUMP .......... WHITEHOUSE
HILLARY .........JAILHOUSE
BERNIE .......... NUTHOUSE
0BAMA .......... OUTHOUSE
Reply With Quote
  #10  
Old 01-29-2008, 09:07 AM
Registered User
 
Join Date: Jun 2005
Location: NJ
Posts: 1,182
Pay the extra $0.50 and use resistor spark plugs!





I'd start w/ that electrical grease on all grounds.
__________________
82 300D....went to MB heaven
90 350 SDL....excercising con rods
Reply With Quote
  #11  
Old 01-29-2008, 11:01 AM
KCM KCM is offline
Registered User
 
Join Date: Jan 2004
Posts: 645
My bet is you got a bad alternator. Did it whine before you put the rebuilt alternator on? If not, then it's the alternator. Rebuilt doesn't mean what it used to any more.

Is the whine affected by engine speed rather than driving speed, and does turning on the headlights, heater blower, and all electrical accessories reduce the noise? Then it's the alternator. Have a car that did the same thing, and changing the alternator fixed the problem. It still always kept the battery charged though. Suspect a diode but never got around to finding out for sure.
Reply With Quote
  #12  
Old 01-29-2008, 11:34 AM
bustedbenz's Avatar
Registered User
 
Join Date: Feb 2007
Location: Valle Crucis, NC
Posts: 2,283
Wow, forgot I'd even started this. Crazy week...

anyway,

*It's an aftermarket radio, not the original. Less than two years old.
*The alternator swap was done well over a year ago, and the alternator puts out steady charging voltage. No reason to suspect it's bad. New voltage regulator went on when we put the alternator on.
*It is engine speed related, not wheel speed, that's how I decided it was the alternator in the first place. Nothing else electrical that's governed solely by engine speed.
*I haven't tried playing with the headlights and things in connection to it.
*It's not a really penetrating whine, just sort of a background whistle. The only time I hear it is if I'm listening to a weak station and therefore have the volume up too high. It may be this and nothing more rather than an electrical problem.

I'll keep an eye on it and check some of these things out. It's not a particularly pernicious problem yet, I just wondered if it was something that was universal.

Thanks, I'll report back if I find anything. Won't have time to check for a while.
__________________


~Michael S.~
Past cars:

1986 300SDL
1987 300SDL
1982 240D
1982 300SD


Current:

1987 300SDL
Reply With Quote
  #13  
Old 01-29-2008, 03:30 PM
Registered User
 
Join Date: Dec 2004
Location: N.W.Connecticut
Posts: 92
I can hear my alternator in my radio

Just my .02 cents--- Were you hearing the alt noise while the radio was on the AM band or on the FM band or both?? Seems to me there are two possible routes for the alt noise to get into your radio. First, the alt noise can be radiating from the alt and being picked up by the antenna. If this is the case opening the hood could increase the response. (If the hood sheet metal is steel). Also disconnecting the antenna from the radio should decrease the response. The other source of alt noise might be associated with the power input leads to the radio. Sometimes it is possible to run the "hot" lead through a feedthru capacitor which is securely grounded. What I am assuming is that the alt noise has components that are in the radio frequecy band,and your radio is treating that noise as a legit radio signal. Oh well,just a thought.best of luck to you. Willie
__________________
Willie White
1980 300SD 116
82 D engine and transmission
If something can go wrong--it will
Reply With Quote
  #14  
Old 01-29-2008, 04:36 PM
bustedbenz's Avatar
Registered User
 
Join Date: Feb 2007
Location: Valle Crucis, NC
Posts: 2,283
I have bigger fish to fry just at the moment. I was wanting to throw it out there but I don't really consider it my biggest problem at the moment.

Thanks for all the input, I've got a list of several things to check and rule out and figure out now.

__________________


~Michael S.~
Past cars:

1986 300SDL
1987 300SDL
1982 240D
1982 300SD


Current:

1987 300SDL
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 09:26 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page